New LED recessed in drop ceiling

I haven't been able to find any information on this either here or via Google...

I'm installing the electrical in the area above what will be a suspended ceiling. Normally, the cans are wired to each other via BX cable strung in the plenum area. The BX is necessary (I assume) because Romex will not satisfy code.
I would like to install LED lights in this ceiling and would like to use "new" LED cans as opposed to LED retrofits that go in existing cans. I have a bunch of existing romex installed above the floor joists and I've removed the old basement lights and boxes and was hoping to run those wires directly down to the new LED lights.
Does the short run (from just above the floor joist to the connection box on the new LED light) have to be BX?

As I read this, I understand that it might not make a lot of sense, but I'll leave it like it is and clarify if need be.

New LED recessed in drop ceiling

By "Plenum" I simply meant the area above the drop ceiling and below the floor of the next level. I didn't mean to imply that there was negative pressure or any features of an actual plenum that were significant in answering the question.
Sorry for that.
-Jim

New LED recessed in drop ceiling

Have you looked into low voltage LED pucks that just push into a hole? You will need a supply transformer somewhere...but the low voltage wiring might save you some code issues...and the low voltage LED's are easier to dim...if that is a feature you want.

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